Numbers k such that 3^k - 20 is prime.

Terms

a(0) =3a(1) =4a(2) =5a(3) =6a(4) =10a(5) =11a(6) =19a(7) =20a(8) =23a(9) =25a(10) =26a(11) =71a(12) =80a(13) =91a(14) =101a(15) =139a(16) =150a(17) =179a(18) =200a(19) =246a(20) =599a(21) =626a(22) =1126a(23) =2215a(24) =4189a(25) =7795a(26) =30626a(27) =66941a(28) =87630a(29) =104388